1. Field of the Invention
The present invention relates to an orthodontic wire retainer. More particularly, the present invention relates to an orthodontic wire retainer which is to be kept in place following an orthodontic treatment of the dental arch till fixation of the arch.
2. Description of the Prior Art
It is common practice to have an orthodontic retainer set in position for a fairly long time following an orthodontic treatment of the dental arch till fixation of the arch. If the dental arch following an orthodontic treatment is allowed to stand, it will return to the pre-treatment condition owing to the so-called "relapse" phenomenon. The retainer is mounted on the dental arch and kept in situ for some time to prevent occurrence of the above event. For this purpose, various types of retainers have heretofore been developed. As illustrated in FIG. 2, the typical conventional retainer is made in such a manner that a metal wire (1), for example a stainless steel wire or a cobalt-chromium wire, which is laid along the anterior surface of the dental arch, is made to extend to the posterior surface of the dental arch and this extension (2) is fixedly secured to a base (3) made of a synthetic resin such as a poly-epoxy compound and molded to fit into the palate.
Because of the presence of the base (3) made of a resin and having a comparatively large thickness in the palate, the conventional retainer not only causes a foreign body sensation in use but has the disadvantage that as the base interferes with the movement of the tongue, the user tends to have difficulties in conversation.
Furthermore, for the reason that said base (3) exists in the palate, the conventional retainer is difficult to use during eating and is often removed temporarily before meals. For the above reasons, it is near to impossibility to use the conventional retain continually so that the benefit of use of a retainer is greatly sacrificed.
In addition, orthodontic treatment is often accompanied by tooth extraction and in such cases the extraction space is at times expanded with time after the orthodontic treatment. Once such an extraction space is formed, the conventional orthodontic retainer cannot exhibit its orthodontic function fully, for its support for the dental arch is substantially solely provided by the metal wire (1) disposed along the anterior surface of the dental arch.
It is a principal object of the present invention to overcome the above-mentioned drawbacks of the conventional orthodontic retainer and provide an orthodontic wire retainer free of a resin base.